1. Field of the Invention
The present invention relates to a wireless LAN system.
2. Description of the Related Art
Wireless LANs remarkably improve the possibility and flexibility of network systems, but security measures are indispensable owing to wireless communication. Limitation of clients who access a wireless LAN requires a mechanism of authenticating a client at an access point when the client requests connection to the access point.
Under this situation, a system of separately preparing an authentication server serving as a server for authenticating a client, and performing authentication between a client, an access point, and the authentication server is standardized as IEEE 802.1x by IEEE. This system is widely used.
At present, many attempts are made to install a wireless LAN system in public environments such as a hot spot. In the hot-spot environment, many unspecified clients exist, and authentication for determining whether a client should be provided with hot spot services is very important.
Whether to permit or inhibit network access is decided on the basis of the authentication results of many unspecified clients. Demands may also arise for assigning clients a plurality of levels and providing different services to the clients. For example, services to be provided to an unregistered client, registered client, and charged client are switched.
In addition to access to services corresponding to the level of a client, access to services provided to lower levels can also be permitted such that a charged client receives services for a registered client and services for an unregistered client.
For example, a technique of limiting access from a cell phone to each electronic device in accordance with the authentication level of the user has been proposed (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2002-232597).
A technique of limiting an access right to schedule information in accordance with the authentication level in a schedule management system is also available (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2002-288394).
The access point of a conventional wireless LAN system is connected to a single network, and only an authenticated client can communicate via the access point and the network.
At the access point of the conventional wireless LAN system, each wirelessly connected client cannot communicate via a network corresponding to the client out of a plurality of networks which provide different security levels and along with this, different services and the like. For example, the access point is connected to a single network. Thus, it is difficult to provide a service of connecting a client who has successfully been authenticated and a client who fails in authentication to different networks. Also, it is difficult to authenticate a client and provide a different service in accordance with the authentication result.